Research killer cells produced against cancer

Japanese researchers are developing killer cells against cancer

01/04/2013

Japanese researchers use so-called T-lymphocyte killer cells to fight cancer cells. Scientists working with Hiroshi Kawamoto of the Riken Research Center in Yokohama have developed cancer-specific killer cells with the help of induced pluripotent stem cells (iPS), which enabled reliable destruction of skin cancer cells in laboratory experiments.

The previous approaches of cancer therapy, such as radiotherapy, chemotherapy and surgery, although sometimes offer quite considerable chances of success, but a truly reliable cure of cancer is often not possible with them. Often the treatment does not start in the desired form. Therefore, researchers around the world are working hard to develop new treatments for cancer. One of the most promising approaches is the use of reprogrammed killer cells to fight tumors. Here, the Japanese research team has now achieved a significant success. Hiroshi Kawamoto and colleagues have produced white blood cell-induced pluripotent stem cells, which they then convert into killer cells that specifically target skin cancer. The study shows „an approach for cloning and expanding functionally antigen-specific CD8 + T cells that could be used in the cell-based therapy of cancer“, write the scientists in the journal „Cell Stem Cell“.

Japanese researchers are developing cancer-specific killer cells from iPS
Previous attempts to combat cancer using cytotoxic T lymphocytes (CTL) failed mainly due to the low life and low availability of artificially generated killer cells. The Japanese research team has now made significant progress here. They used T-lymphocytes designed to fight specific skin cancer cells, programmed the cells back, and used the resulting iPS to develop novel cancer-specific killer cells that the body can not produce itself. These had a significantly longer lifespan than ordinary CTL, but otherwise showed the properties of the original starting cells. With the receptors on their surface, they were able to recognize and attach to the skin cancer cells. In the laboratory experiments, the newly developed killer cells had more than 90 percent of the required properties for combating skin cancer cells, report Hiroshi Kawamoto and colleagues.

Medical potential of induced pluripotent stem cells
The use of induced pluripotent stem cells holds enormous medical potential without being burdened with comparable ethical problems such as embryonic stem cell research. In this way, patient-specific cells can be generated for different applications. However, the process also involves some risks. For example, studies by US scientists at the University of California, the San Diego School of Medicine, and the Scripps Research Institute have already identified severe genetic changes in pluripotent stem cell lines in 2011. In the production of iPS, therefore, changes in genetic material may occur, which in turn cause an increased risk of cancer. The treatment of skin cancer with the newly developed cells of the Japanese researchers, could possibly cause cancer. Here, further studies on the risks of iPS are required before an application in cancer therapy can be tested. Study author Hiroshi Kawamoto emphasized that „The next step is to investigate whether these regenerated T lymphocytes in the human body can specifically recognize and kill tumor cells and have no effect on the other cells.“ In the event that all other tests are positive, the cells could in future be directly injected into the patient for cancer therapy, explained the physician.

Increasingly critical voices on stem cell research
To what extent the expectations of the Japanese researchers in the treatment of cancer with the newly developed killer cells will be met, is so far difficult to estimate. Although researchers worldwide are currently focusing increasingly on the potential of induced pluripotent stem cells, recent criticisms of the process, for which Shinya Yamanaka from the Japanese Kyoto University in Japan received the Nobel Prize for Medicine in 2012, have also accumulated. While some scientific papers have addressed the weaknesses and risks of iPS, others have criticized the premature publication of possible research achievements due to the extreme competitive pressures among researchers. For example, long-term effects would often not be adequately considered in the studies. Despite the enormous medical potential that the medical profession ascribes to the iPS, especially in the treatment of previously incurable diseases such as cancer or Parkinson's disease, the results of stem cell research have so far fallen far short of expectations. (Fp)

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Image: Matthias M, Wikipedia